Which of the following would illustrate a quadratic relation between the dependent and independent variables when graphed?

A. a graph of mass of water vs. the volume of water in a drinking glass

B. a graph of the area a of a circle vs. its radius r (a = Ο€r2)

C. a graph of the equation a = 1/ b

D. a graph of distance vs. time for a car moving at constant speed

Respuesta :

Answer: option A. a graph of the area of a circle vs. its radius r (A = Ο€rΒ²).



Explanation:



A quadratic relation between the dependent and independent variables shows the independent variable raised to the power of 2.



This is it is a polynomial with general form axΒ² + bx + c, whewre a, b, and c, named coeficients, Β are constants.



The function is y = Β axΒ² + bx + c, where x is the independent variable and y is the dependent variable.



As stated in the question, the area of a circle is given by A = Ο€rΒ².



In this case, A is the dependent variable and r is the independent variable.



Ο€ is assumed as the coefficient of the quadratic term, and the other coefficients are assumed 0, since there are no either terms on r or constants.



The equation a = 1/b Β is an inverse relation, not a quadratic relation.



The relation of distance vs. time for a car moving at constant speed is a linear relation of the kind v = u + st.



The mass of water vs. the volume of water in a drinking glass is a direct relation, mass = density Γ— volume



Therefore, the only quadratic relation is shown by Β a graph of the area of a circle vs. its radius r.